Wholly aromatic polyimides are well known and are prepared by reacting an aromatic diamine with an aromatic tetracarboxylic acid dianhydride under conditions which result in initial formation of a polyamic acid. On further reaction, the polyamic acid cyclizes to form the polyimide. Polyimides are well known for their outstanding engineering properties and, in particular, their thermal, oxidative and chemical resistance. Polyamides are formed by reacting a diamine with an aromatic dicarboxylic acid dichloride or diester, as opposed to the aromatic tetracarboxylic acid dianhydride, which then reacts to form the polyamide. Polyamides, like polyimides, have good thermal stability and excellent strength. Processing is often difficult because of their limited solubility in many organic materials.
Recently, Hergenrother, et al. at Langley Research Center, had an article published in the Journal of Polymer Science: Part A: Polymer Chemistry, vol. 25, 1093-1103 (1987) pertaining to new developments in polyimides. Specifically, polyimides containing both carbonyl and ether connecting groups were reported. These new polyimides were considered to be highly processable, and had excellent solvent and impact resistance. In the preparation of these polyimides containing carbonyl and ether connecting groups, the diamine monomers, particularly 1,3-bis[4-(4-aminophenoxy)benzoyl]benzene, were synthesized by aromatic nucleophilic displacement of fluorine from an activated substrate, e.g., the above-mentioned diamine was made by reaction of 1,3-bis[4-fluorobenzoyl]benzene with 4-aminophenol in the presence of potassium carbonate. More particularly, the process route is shown by the following formulas: ##STR1##
U.S. Pat. No. 4,393,162 discloses the preparation of polyimides and copolyamides prepared from di(aminophenoxy)ethane as the diamine monomer. The diamine monomer is then reacted with aromatic or aliphatic diacids.
U.S. Pat. Nos. 4,687,833; 4,339,568; and 4,657,990 and European Patent 275,035 disclose various aromatic and chain extended polyketones which were alleged to have excellent toughness, fabricability, high temperature and solvent resistance. In the '833 patent, a diphenol was coupled with a monomeric poly(arylether ketone) segment via a nucleophilic route using a base and aprotic solvent. The route was similar to that of Hergenrother, et al. for preparing the diamine monomer for preparing polyimides, except for the substitution of a diphenol for an aminophenol.
U.S. Pat. No. 4,663,484 discloses a process for producing diaminoalkyl diphenyl ethers by reacting alkylphenols with alkylhalobenzenes in the presence of a copper catalyst. These alkyldiphenyl ethers then were reacted with hydroxylamine to form the corresponding dioximes and then were subjected to a Beckman rearrangement followed by hydrolysis of the resulting diacetamino-alkyldiphenyl ether.
U.S. Pat. Nos. 3,063,966 and 4,101,487 discloses a process for producing aromatic polyamides by reacting an aromatic diamine with an aromatic diacid halide.